Thomas officer



T. OFFICER.

ROGK DRILL.-

(No Model.)

10.580,461. PatQntedApr. 13, 1897.

INVENTUR.

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SPECFICATION forming part of Letters Patent No. 580,461, dated April 13, 189'17.

AApplication filed August 12,

To a/ZZ whom it may con/cern."

Beit known that LTI-IOMAS OFFICER, a resi* dent of Claremont, in the county of Sullivan and State of New Hampshire, have invented a new and useful Improvement in Rock-Drills; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to rock-drills.

The special form of rock-drill t'o which my invention is applicable is that in which acylinder is employed with a piston operating therein and a spiral rifle-bar Working ina nut in the piston, together with mechanism at one end of said riflebar for permitting of the rotation of the ride-bar upithe descentv of the piston, but holding said ride-bar from rtation upon the upward stroke of the pis`- p ton, Whereloyethe piston itself is turned on the upward stro-ke.` l

The present invention relates to a new and improved form of mechanism for holding the rifle-har during the -upward stroke of the piston and for releasing said mechanism in case the drill-bit should be prevented from turning.

My invention comprises certain new features in this form of mechanism, all of which will be fully hereinafter set forth andclaimed. To enable others skilled in the art to make and use my invention, I will describe the same morefully, referring to the `accom pan yyingdrawings, in Which-- Figure l is a vertical section of the upper portion of a rockdrill to which my invention is applicable. Fig. 2 is a section on the line 2 2, Fig. 1. Fig. 3 is a perspective View of one of the inclined blocks. Fig. 4 is a view of one of the rollers. Fig. 5 isabottom view of the friction-head, and Fig. Gis a side View of same. i

Like letters indicate like parts in each of the igures. l ,y p

As the form of rock-drillY to' which my invention is applicable issowell-known, I have not deemed it necessary to illustrate the valve mechanism and the lower part of the apparatus, as there are different forms of valve mechanism which nia-y be used, and such valve mechanism forms no part of my invention.

The letter a represents the upper portion 1896. Serial No. 602,498. (No model.)

of a suitable cylinder having the piston-chamber a therein, together with valve-controlled ton-rod extends down therefrom, and which i has attached theretoa suitable drill-bit. The

The friction-head h has the seats 1l at the lower end thereof, within which the inclined blocks j are adapted'to fit, said inclined blocks having shoulders j', adapted to engage with corresponding shouldersj 2 in the head h,whereby said Blocks are held from working in should they become worn. These blocks j have the grooves k formed therein, so that when said blocks are in position said grooves coincide with the eccentric groove k', formed around the lower portion of the head h. Secured within the eccentric groove k.' are the springs Z l', the ends of said springs Z l entering the grooves k in the inclined blocks j. These 'springs l Z' normally press the rollers m into contact with the teeth of the ratchet-head g, whereby said ratchet-headis permitted to turn in one direction, but is prevented from turning in the opposite direction by said rollers m, as will more'fully hereinafter appear..

The outer faces of the inclined blocks j are in contact with the inner walls at the upper end of the cylinder a.

. The head h has the annular shoulder n, which rests upon the upper end of the cylinder a. The said head h has also a shoulder n at the upper end thereof, and resting upon i loo o. The lower ends of the side rods p extend joint and does awayiwith packing,

down through the lower head of the cylinder. (Not shown.) I

The yoke o is eountersunk at o' to receive the projection o2 of the head hin order to keep the yoke central.

By the employment of the rods p and the springs p2 the yoke oisv forced down onto the head h and holds the"steampressure in the' cylinder. The head being ground onto the end of thevv cylinder at n makes a 'steam-tight y The oil-plug q vpasses down through the yoke o and is secured onto the head h, whereby oil may be admitted to the oil-chamber r, formed within the head h..

When my improved rock-drill is in operation, as the rpiston b descends the rifle-bar d will turn in the direction indicated by the arrow in Fig. 2. On the upward stroke, however, of the piston b the rifle-bar is prevented from turning by means of the rollers m, which are forced into contact with the inclined faces of the inclined blocks jc The ride-bar being held against rotation in thisway, upon the descent of the piston the piston and the riliebar nut e will be compelled to turn. In case, however, the drillbit should be held from 'turning in the lrock for any reason, and it is impossible for it to turn, then suincient pressure will be exerted to move the head h, whereby the strain on the drill is removed and thel piston ascends without injury to the drill parts. Y

By? the employment of the-herein-described mechanism I obtain greater frictional contact, as the head is held between the yoke and the upper end of the cylinder, while at the same time the rollers, on being forced to the inclined blocks, force said blocks outwardly against the inside of the cylinder, making additional friction to that on end of cylinder and on yoke to hold the ratchet from turning when the piston is being turned, and the head, together with the inclined blocks, will only slide when the piston turns'harder than it should or is caught so that it cannot turn.

What I vclaim as my invention, and desire to secure by Letters .Patent, is-

l. In a rock-drill, the combination with a suitable cylinder having a reciprocating piston therein, of a spiral riiie-bar engaging said piston, a ratchet-head on said rifle-bar, a friction-head interposed between said cylinder and a yoke above, inclined blocks fitting in said head and engaging the inner walls of said cylinder, rollers engaging said blocks and the teeth of said ratchet-head, and springs acting on said rollers, substantially as set forth.

2. In a rock-drill, the combination with a suitable cylinder having a reciprocating piston therein, of a spiral riiie-bar engaging said piston, a ratchet-head on said rifle-bar, a friction-head interposed between said cylinder anda yoke above, said friction-head having an eccentric groove formed therein, inclined blocks iitting in seats lin said friction-head and having grooves coinciding with said eccentric groove, rollers engaging said' blocks and the teeth of said ratchet-head, and springs in said grooves engaging said rollers, substantially as set forth.

3. In a rock-drill, the combination with a suitable cylinder having a reciprocating piston therein, of a spiral rifle-bar engaging said piston, a ratchet-head on said riie-bar, a fric tion-head having a recess-therein adapted to receive said ratchet-head, said friction-head bei-ng interposed between the upper end of the cylinder and a yoke above, and pawl mechanism on said friction-head adapted to engage the teeth of said ratchet-head, substantially as set forth.

4. Ina rock-drill, the combination with suitable cylinder having a reciprocating piston therein, of a spiral rifle-bar engaging said piston, a ratchet-head on said rifle-bar, a friction-head having a recess therein to receive said rat-ch et-head, said friction-head being interposed between the upper end of said cylinder and a yoke above, pawl mechanism on said friction-head adapted to engage the teeth of said ratchet-head, said friction-head having an oil-chamber therein and a passage leading thereto, substantially as set forth.

In testimony whereof I, the said THOMAS OFFICER, have hereunto set my hand.

. THOMAS OFFICER.

"itnesscsz H. W. PARKER, E. J. TENNEY. 

